1. Field of the Invention
The present invention relates to recording and/or viewing a videoconference, and, more particularly, to switching an input to a videoconference recording and/or viewing device between multiple available sources in a videoconference system.
2. Description of the Related Art
A videoconference environment typically includes a plurality of conference sites, commonly referred to as endpoints, which are geographically separated but electronically linked together to enhance collaboration between and among individuals at the various conference sites. A videoconference system attempts to replicate the interpersonal communication and information sharing which would occur if all the participants were together in the same room at the same time.
A videoconference typically includes two or more endpoints coupled together via digital communication lines. For example, in a point-to-point conference, two endpoints are coupled in a videoconference. One endpoint dials the other endpoint directly to initiate the videoconference. More than two endpoints may be coupled in a multipoint videoconference. In a multipoint videoconference, each endpoint dials a multipoint control unit (MCU) which couples the endpoints in a common videoconference.
Each endpoint typically transmits and receives conference information (e.g., audio and video information) to and from the other endpoint(s). Each conference site includes at least one source of conference information. For example, each endpoint has one or more audio and video sources from which to select for transmission to the other endpoint(s). Typically, only one audio signal and one video signal are transmitted from each endpoint. Audio sources at the endpoint are usually mixed together to form a single audio signal for transmission, but video sources are individually chosen to be the transmitted video signal. Exemplary sources include microphones, cameras and/or computer systems. Exemplary video sources include physical video sources such as cameras for viewing conference participants and/or documents (e.g., paper documents) and graphical video sources such as computer systems for generating and annotating slides (e.g., computer graphics).
As noted, videoconferencing involves the transfer of conference information from endpoint to endpoint. Conference information includes video and/or audio information. Video information includes physical information captured by a camera and graphical information generated by an information processing system such as a computer system. Physical information refers to recorded information providing a representation of "real world" information such as an image of a conference participant and/or an image of a slide or paper document. Physical information is captured and recorded, for example, by a physical information source such as a camera. Graphical information refers, for example, to graphical data information which is generated and displayed by an information processing system on a computer system display monitor or an overhead projector. A graphical information source is any data information generation, annotation and/or display such as a computer system. Graphical information may be provided on the same display or on a different display as physical information from a camera. Audio information is typically transmitted with corresponding video information.
Ideally, endpoints transmit conference information from a conference focus source to each of the other connected conference sites. As used herein, the conference focus source is the source providing the conference information which would have the attention of participants in the conference were the participants located together in the same room at the same time. The focus of a conference may include, and may switch between, a primary speaker, a participant asking a question, a data screen provided by a slide projector or computer system, or some other source of conference information. Thus, the conference focus frequently shifts from one source of conference information to another during the course of a typical videoconference. Determining the focus of a videoconference is a well-known challenge in the design of videoconference systems, and often requires manual intervention on the part of conference participants.
Videoconference systems often include a videocassette recorder (VCR). Integration of a VCR provides the ability to record a videoconference. Ideally, a video recording of a videoconference switches to whichever source is the current focus of the conference (i.e., the conference focus source). Switching the source provided to the VCR to record the focus of the conference typically requires user interaction such as pressing a button to select the source for recording.